Objectives of this proposal are to define the major determinants of FFA flux and examine liver and muscle FFA metabolism. This study is now resuming after a several year delay to develop new methods to measure intramuscular fatty acid metabolism. We have added stable isotopes to this study in order to allow the partitioning of fatty acids into intramuscular triglycerides, non-esterified fatty acids, and long-chain acylcarnitines. We are no longer placing femoral artery or femoral vein catheters as part of this study. The positive results from the preliminary studies in this protocol served as the basis for competing renewal for the NIH grant under which this is performed.